FreeCalypso > hg > fc-small-hw

annotate lunalcd2/README @ 76:16fd456fdb40

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
lunalcd3.pcb: layout changes around top bracket
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 18 Nov 2021 06:55:23 +0000
parents a2ce85275f63
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
55
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
1 Formike KWH020ST23-F01 is a candidate LCD module being considered for our
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
2 FreeCalypso Libre Dumbphone dream handset. Prior to building the actual
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
3 handset, we will need to build our FC Venus development board, and prior to
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
4 starting the design of this Venus board, we are going to test the proposed LCD
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
5 module in our currently existing Luna environment. The modular LCD subsystem
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
6 board being designed in this directory is intended to be a drop-in replacement
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
7 for our previous Luna LCD board from 2020-04 (lunalcd1 directory), to be
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
8 connected to the same Caramel/C2 motherboards, with the resulting system
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
9 configuration still being Luna (not Venus).
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
10
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
11 In addition to changing out the LCD module, the backlight driver circuit is
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
12 being changed to the MAX1916-based one described in FreeCalypso Handset
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
13 Specification section 1.4.4, with a set of DIP switches selecting different LED
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
14 currents - the intent is to find appropriate LED currents for the different
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
15 display brightness modes that will be needed in the actual handset. A current
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
16 measurement resistor is also being inserted in the LCD (not backlight) power
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
17 supply path - we will be exercising the LCD controller/driver chip's power-
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
18 saving sleep modes, and we need to be sure that they actually reduce the 2.8V
a2ce85275f63 lunalcd[12]/README written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
19 supply current draw as expected.